DEAD ZONE OVER A HORIZONTAL TUBE IMMERSED IN A FLUIDIZED BED.

In a fluidized bed, defluidized or 'dead' zones appear as a result of the low velocity present in the wake regions of immersed surfaces, in near-wall regions, and over the blocked portions of the distributor plate. In a fluidized bed combustor or reactor, the lack of particle mixing in dead zones can lead to corrosion of immersed surfaces, reduction of combustion efficiency, and loss of heat transfer. Results of a study on dead zones show that they decrease with increasing air velocity and are relatively insensitive to particle size.